KR102667052B1 - Beam Splitting Handoff System Architecture - Google Patents

Abstract

A beam split handoff system architecture and a method for using the same are disclosed. In one embodiment, the method includes: generating a first beam with a single electronically steered flat-panel antenna to track a first satellite; generating a first beam to track a first satellite while simultaneously generating a second beam to track a second satellite with a single electronically steered flat-panel antenna; and handing off traffic from the first satellite to the second satellite.

Description

Beam Splitting Handoff System Architecture

This patent application is based on the corresponding Provisional Patent Application Nos. 62/681,552, filed June 6, 2018, and entitled “BEAM SPLITTING HAND OFF SYSTEMS ARCHITECTURE” and filed June 6, 2019. Priority is claimed and incorporated by reference to Non-Provisional Patent Application No. 16/432,624, entitled “BEAM SPLITTING HAND OFF SYSTEMS ARCHITECTURE,” filed on May 5.

Embodiments of the present invention relate to the field of wireless communications; In particular, embodiments of the present invention relate to generating multiple beams simultaneously from a single satellite antenna to facilitate handing off communications between two satellites.

A satellite terminal attempting to maintain communication with a constellation of nonstationary satellites can point to a given satellite only while that satellite is within the terminal's field of view. When a satellite goes out of sight, the terminal should point to another satellite that has recently come into view. With only a single beam to point at any given satellite at any time, the RF connection will be lost during transition to another satellite. In other words, the satellite will have to block connections with satellites that are out of its field of view so that it can connect with new satellites that are coming into or are already in its line of sight. This break-before-make (BBM) connection provides time for the antenna to switch pointing angles, time for the tracking algorithm to optimize pointing for the new satellite, and locking for the new carrier. resulting in data outage, caused by the time for the modem to lock and the time for the network to re-establish the end-to-end connection. do.

The present invention was invented in consideration of the above, and a beam splitting hand off system architecture and a method for using the same are disclosed.

In one embodiment, the method includes: generating a first beam with a single electronically steered flat-panel antenna to track a first satellite; generating a first beam to track a first satellite while simultaneously generating a second beam to track a second satellite with a single electronically steered flat-panel antenna; and handing off traffic from the first satellite to the second satellite.

The invention will be more fully understood from the detailed description given below and the accompanying drawings of various embodiments of the invention, but should not be taken to limit the invention to the specific embodiments, which are for illustration and understanding only.
1 is a flowchart of an embodiment of a method for using a satellite antenna for communication.
Figure 2 is a flowchart of an embodiment of a method for using a satellite antenna for communication.
Figure 3 illustrates an embodiment of a beam splitting antenna system.
Figure 4 is a block diagram of an alternative beam splitting antenna system.
FIG. 5A is a timing diagram of antenna beam switching for tracking and handing off satellites.
5B illustrates an example of transmit (Tx) beam splitting and handoff and corresponding timing diagram.
Figure 6 illustrates a schematic diagram of one embodiment of a cylindrically fed holographic radial aperture antenna.
Figure 7 illustrates a perspective view of a row of antenna elements including a ground plane and a reconfigurable resonator layer.
Figure 8A illustrates one embodiment of a tunable resonator/slot.
Figure 8B illustrates a cross-sectional view of one embodiment of a physical antenna aperture.
9A to 9D illustrate an example of multiple layers for creating a slotted array.
Figure 10 illustrates a side view of one embodiment of a cylindrically fed antenna structure.
11 illustrates another embodiment of an antenna system with outgoing waves.
Figure 12 illustrates one embodiment of the arrangement of matrix drive circuitry for antenna elements.
Figure 13 illustrates one embodiment of a TFT package.
Figure 14 is a block diagram of one embodiment of a communication system with simultaneous transmit and receive paths.

In the following description, numerous details are set forth to provide a more thorough explanation of the invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form rather than in detail, to avoid obscuring the present invention.

Embodiments of the present invention track nonstationary and stationary satellite constellations and maintain a connection during transition from one satellite to another. Includes a method and system architecture for handoff of satellite traffic between simultaneous and independent beams. In another embodiment, this includes handoff of transmit traffic. By using the techniques disclosed herein, make-be-break (MBB) handoff is possible between non-geostationary, geostationary satellites or spacecraft.

The technology described herein includes many innovations such as those described below. For example, in one embodiment, two beams are generated simultaneously with one electronically steered flat antenna to track two satellites within a constellation and then seamlessly hand off traffic from the initial satellite to the new subsequent satellite. .

In one embodiment, a single electronically steered antenna is used to implement a make-before-break (MBB) connection in which an RF connection is established with a new satellite before the RF link is broken with the existing satellite.

1 is a flowchart of an embodiment of a method for using a satellite antenna for communication. In one embodiment, the process is performed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, etc.), software (e.g., software running on a chip), firmware, or a combination thereof. In one embodiment, the satellite antenna is a flat-panel antenna. In another embodiment, the satellite antenna is an electronically steered flat-panel antenna. An example of such an electronically steered flat-panel antenna is described in greater detail below.

1, the process includes operating an antenna (e.g., an electronically steered flat-panel antenna) in a single beam configuration (or mode) in which the antenna is generating a single received beam while tracking to track a first satellite. The order is initiated by processing logic (processing block 101). In one embodiment, operating the antenna in a single beam configuration involves generating an electronically steered antenna beam pattern for beamforming and a set of RF radiating antenna elements (a). A set of RF radiating antenna elements (e.g., but not limited to, an electronically steered flat-panel antenna with surface scattering metamaterial antenna elements, such as, but not limited to, those described below) It involves directing a beam pattern to a spherical surface and generating a receive beam with an RF radiating antenna element based on the antenna pattern.

The processing logic then operates the antenna in a multi-beam configuration (e.g., a dual-receive beam configuration) in which the antenna is generating two or more receive beams during tracking to track multiple satellites, and simultaneously generating at least one additional receive beam with the antenna to track the second satellite while continuing to generate a receive beam to point and track the first satellite (processing block 102). In one embodiment, when the multi-beam mode is in the dual-beam mode, the antenna generates two received beams to point and track two satellites, where the two satellites are connected to the antenna during the previous single-beam configuration. Includes the satellite that was pointed and tracked and a new satellite that began tracking with a second beam while the antenna acquired a signal and was in a multi-beam configuration.

Then, after tracking the additional satellite, the processing logic returns to operating the antenna in a single beam configuration with a single receive beam pointing and tracking the new satellite from which signals were acquired during the multi-beam configuration, but not the previous single beam configuration. and handing off traffic from the satellite being tracked to the new satellite while in configuration (processing block 103). In one embodiment, handing off traffic is performed seamlessly such that the connection is maintained throughout the transition from a previously tracked satellite to a new satellite.

Figure 2 is a flowchart of an embodiment of a method for using a satellite antenna for communication. In one embodiment, the process is performed by processing logic, which may include hardware (e.g., circuitry, dedicated logic, etc.), software (e.g., software running on a chip), firmware, or a combination thereof. In one embodiment, the satellite antenna is a flat-panel antenna. In another embodiment, the satellite antenna is an electronically steered flat-panel antenna. An example of such an electronically steered flat-panel antenna is described in greater detail below.

2, the process includes forming a first set of RF radiating antenna elements (e.g., surface scattering metamaterial antenna elements, such as, but not limited to, those described below) on the antenna aperture of the antenna. )) is initiated by processing logic that controls an electronically steered flat-panel antenna to generate a single receive beam that points and tracks the first satellite using ( Processing block 201). In one embodiment, the processing logic includes generating an electronically steered antenna pattern for beamforming, directing a received beam pattern to an antenna aperture of an antenna having a set of RF radiating antenna elements, and based on the pattern. Control the antenna by generating a single receive beam with a first set of RF radiating antenna elements.

While tracking the first satellite, processing logic determines to switch the antenna to a two-receive beam configuration in which the antenna is simultaneously generating first and second receive beams (processing block 202). In one embodiment, this decision to switch the antenna to a two beam configuration is made when the antenna is out of sight of the first satellite and needs to find a second satellite to continue communications.

After the decision to switch to the two receive beam configurations, processing logic generates a second beam to acquire signals from a second (different) satellite while continuing to generate a first beam to track the first satellite. Control the antenna so that the first and second received beams are generated simultaneously using each of the two sets of RF radiating antenna elements of the antenna aperture (processing block 203), and then the second received beam is generated simultaneously using the second beam. Acquire signals from the satellite (processing block 204). In this case, the first beam is pointing and tracking the first satellite while the second beam is pointing and tracking the second satellite.

In one embodiment, the first and second beams point to carriers at different frequencies. In one embodiment, the first and second beams have different antenna gains, where the gain for the second beam is lower than the gain for the first beam. In one embodiment, this occurs when a second beam is used to acquire a signal from a second satellite. In one embodiment, the second beam is wider than the first beam when used to acquire a signal from a second satellite. In one embodiment, the beam is made wider to capture the signal when there is some uncertainty about the exact location of the signal. In one embodiment, the amount to widen the beam depends on the degree of uncertainty regarding the location of the signal. In one example embodiment, if the beam is less than 2 degrees wide during pointing and tracking, the beam for acquisition is broadened to (but is not limited to) a width of approximately 10 degrees. It should be noted that this is just an example and the beam is not limited to 10 degrees in width during acquisition. However, if the beam is too wide, there is a risk of capturing other satellites.

In one embodiment, two sets of RF radiating antenna elements for simultaneously generating two beams are different but part of the RF radiating antenna elements of the antenna. In one embodiment, two sets of RF radiating antenna elements are provided to simultaneously generate two beams when operating the antenna in a dual-receive beam configuration. Includes some or all of the RF radiation antenna elements used to generate a single beam.

In one embodiment, the two sets of RF radiating antenna elements are of different numbers (e.g., 75% of the antenna elements used to generate the first beam and 25% of the antenna elements used to generate the second beam during signal acquisition). %) of RF radiating antenna elements. The number of elements used to generate each beam depends on the satellite for minimum gain level. In one embodiment, for a particular satellite/scenario, there may be a 10+ dB signal-to-noise ratio (SNR), so the two radiation patterns may be offset by that much. However, in other scenarios a difference greater or less than 10+ dB may be sufficient.

In one embodiment, the antenna aperture includes a set of RF antenna elements dedicated for use in signal acquisition of new satellites with the secondary beam.

In one embodiment, the second and third sets of RF radiating antenna elements are in a ring around a central feed for the feed wave, further comprising each ring of the second set of RF radiating antenna elements. is between the rings of RF radiating antenna elements in the third set of RF radiating antenna elements. In one embodiment, the second and third sets of RF radiating antenna elements are in a ring around a central feed for the feed wave, and the second set of RF radiating antenna elements is in a ring of RF radiating antenna elements of the third set. In comparison, it is located in the ring closest to the central feed. Examples of rings are described in more detail below. For example, in Figure 6, all odd or even rings are used for the second set of RF radiating elements, while other rings are used for the third set of RF radiating elements. Likewise, in Figure 6, the set of rings closest to the cylindrical feed is used for the second set of RF radiating elements, while the other ring is used for the third set of RF radiating elements.

In one embodiment, the second pattern applied to the RF radiating element to point the second received beam indicates the predicted location of the second satellite. In one embodiment, the predicted position is based on commanded two-line elements (TLE).

After acquiring the signal of the second satellite, the processing logic is configured to configure a dual-receive beam configuration (mode) in which the antenna is simultaneously generating the first and second receive beams to track each first and second satellite. ) to control the antenna to operate (processing block 205). In one embodiment, when in dual-receive beam mode, the antenna generates two receive beams to simultaneously point and track two satellites, wherein the two satellites receive a single signal before the antenna acquires the signal of the second satellite. - Includes a satellite that was pointing and tracking during the beam configuration and a second satellite that acquired signals and began tracking while the antenna was in the multi-beam configuration.

Then, after tracking of the second satellite has begun, the processing logic reverts to operating the antenna in a single-beam configuration with a single receive beam pointing and tracking the second satellite, but with no traffic from the first satellite to the second satellite. and handing off (processing block 206). In one embodiment, handing off traffic is performed seamlessly so that the connection is maintained throughout the transition from the first satellite to the second satellite. In one embodiment, handing off traffic between a first satellite and a second satellite is effected in the well-known manner of switching traffic between satellites.

The techniques described above are performed by antennas used in satellite communications. In one embodiment, the antenna is an electronically steered plane-plane having a plurality of electronically controlled radio frequency (RF) radiating antenna elements (e.g., surface scattering metamaterial antenna elements or resonators as described in more detail below). A panel antenna aperture, and the antenna aperture generates a first beam to the antenna aperture to track a first satellite, and simultaneously generates the first beam and sends a second beam to the antenna aperture to track a second satellite. and one or more processors coupled to the antenna aperture to control the antenna aperture to handoff traffic from the first satellite to the second satellite. In one embodiment, the processor seamlessly hands off traffic between the first satellite and the second satellite such that connectivity is maintained throughout the transition from the first satellite to the second satellite.

In one embodiment, prior to generating the second beam to track the second satellite, the processor configures the antenna aperture to generate the second beam to acquire a signal from the second satellite while generating the first beam. control. In one embodiment, the processor is configured to configure respective first and second sets of radio-frequency (RF) radiating antennas in the antenna aperture to generate respective first and second beams to point to carriers of different frequencies. Generate first and second patterns for application to the first and second sets of elements.

3 is an example of a satellite antenna architecture that can generate one or two receive beams simultaneously to facilitate handing off communications between two satellites.

Referring to FIG. 3, a host processor 302 receives satellite positions (e.g., latitude and longitude) and polarization information and, in response to these inputs, generates an antenna system module (ASM). ) Performs antenna receive pointing by generating pointing and tracking information that is provided to and controls the antenna element of the antenna aperture of 301. Examples of such antenna apertures with RF radiating antenna elements (e.g., surface scattering antenna elements or resonators) are described in greater detail below. In one embodiment, pointing and tracking information is associated with electronically controlled antenna wave patterns used to control RF radiating antenna elements as described herein.

In one embodiment, pointing and tracking information includes pointing angle (eg, theta, phi), frequency information, and symbol rate information. The theta range may be [0,90] degrees, and the pi range may be [0,360] degrees. In one embodiment, host processor 302 also generates polarization values that are provided to the antenna aperture of ASM 301. Polarization values can range from [0,360] degrees. In one embodiment, the polarization value is generated by the host processor 302 in a manner well known in the art.

The receiving portion of the antenna aperture of ASM 301 uses the new pointing angle to generate a beam to obtain RF signals from the satellite and provide them to modem 303. In one embodiment, when only one set of pointing information is sent by the host processor 302 to ASM 301, the antenna aperture of ASM 301 (as opposed to that used for transmission) is used for receiving and transmitting (as opposed to transmitting). A single receive beam is generated using all RF radiating antenna elements designated for receive transmissions, and the receive beam is used to acquire RF signals from the satellite.

In response to the received RF signal, modem 303 generates receive metrics (eg, SNR, C/N, etc.) in connection with the received Rx signal. In one embodiment, the reception metric determines whether a satellite signal is discovered based on whether the signal meets one or more predetermined criteria (e.g., SNR or C/N greater than a predetermined threshold) in a manner well known in the art. Indicates whether it has been done or not.

In one embodiment, host processor 302 provides two sets of pointing and tracking information to the antenna apertures of ASM 301, each set of pointing and tracking information allowing ASM 301 to transmit beams 1 and 2. It is intended to control different sets of antenna elements of the antenna aperture of the ASM 301 in order to be able to generate . That is, the host processor 302 sends two sets of pointing and tracking information to the ASM 301 to generate two receive beams simultaneously using different sets of antenna elements in the antenna aperture of the ASM 301. In one embodiment, the two receive beams split a set of antenna elements into two groups (e.g., all different rings of antenna elements, or all different antenna elements in a ring or distribution, or randomly distributed). and by forming two independent beams with the same or different frequencies within the dynamic bandwidth of the corresponding element type. This may be in a different theta or the same theta.

In one embodiment, to generate an electronically steered antenna pattern, the host processor 302 sends commands to the antenna control process (ACP) module on the ASM 301 to begin tracking the target satellite. , In response to the information, the ACP module sends setup information and continuously calculates and sends pointing vectors to the service. In one embodiment, the ACP module includes setup and pointing information consisting of polarization value and operating frequency (e.g., f1, f2) for the antenna aperture in the ASM 301 as setup information, and pointing information. A Poynting vector with theta, phi, and linear polarization angle (LPA) is sent to the pattern generation service.

In response to the setup and pointing information, the service controls antenna elements (e.g., RF radiating antenna elements (e.g., metamaterial scattering antenna elements)) of the antenna aperture to form two receive beams. Provides a plurality of electronically steered antenna patterns. In one embodiment, this service includes software services executed by one or more processors of ASM 301. In another embodiment, this service includes hardware in ASM 301.

In one embodiment, the pattern generation service loads beamforming parameters into the FPGA corresponding to the pattern. In response, the FPGA outputs the pattern to the antenna elements of the electronically steered antenna in the form of digital-to-analog (DAC) values (for each pattern). In particular, the DAC value for each antenna element of the antenna aperture is calculated by the FPGA using beamforming parameters provided by the pattern generation service. Then, the FPGA outputs a control signal to the antenna element to drive the calculated pattern. In one embodiment, the DAC value controls a thin film transistor (TFT) to control an antenna element in the antenna aperture (not shown) to generate a beam. Examples of TFTs and their control are described in more detail below.

After each of the two beams, Beam 1 and Beam 2, are formed in response to the pattern generated by the pattern generation service of ASM 301, the receiver on ASM 301 receives the signal returning from the utilization of each receive beam and It is provided to the diplexer (305). From the diplexer 305, the signal is processed by a Low Noise Block (LNB) 306, which provides a noise filtering function and a down conversion and amplification function in a manner well known in the art. amplification function). 3, it should be noted that in one embodiment, the signals from the two beams have different frequencies, so the LNB 306 covers both frequencies simultaneously. In one embodiment, LNB 306 is in an outdoor unit (ODU). In another embodiment, LNB 306 is integrated into an antenna device.

After signal processing by the LNB 306, the signal is directed to couple the energy from the received signal output from the LNB 306 to the Rx power divider 343 and the modem 303 (as signal 331). It is sent to the coupler (344; directional coupler). In one embodiment, directional coupler 344 is a 10 dB directional coupler; However, other couplers may be used.

The Rx power divider 343 splits the signal received from the directional coupler 344 into two signals and sends one signal to the tracking receiver 341 and the other signal to the tracking receiver 342. In one embodiment, the signal is split based on frequency such that the signal associated with beam 1 is sent to one of the tracking receivers 341 and 342, while the signal associated with beam 2 is sent to the other of the tracking receivers 341 and 342. do. When the antenna operates in single-beam mode and produces only one received beam, Rx power divider 343 provides one signal to only one of the tracking receivers 341 or 342 and provides a signal to the other. Not provided. In one embodiment, the Rx power divider is a diplexer. Alternatively, Rx power splitter 343 includes a power splitter or frequency adjustable filter.

In response to signal 331, modem 303 processes signal 331 in a manner well known in the art. More specifically, the modem 303 includes an analog-to-digital converter (ADC) to convert the received signal output from the directional coupler 344 into a digital format. Once converted to digital format, the signal is demodulated by a demodulator and decoded by a decoder to obtain encoded data for the received wave. The decoded data is sent to a controller that sends it to its destination (e.g., a computer system).

Modem 303 also includes an encoder that encodes the data to be transmitted. The encoded data is modulated by a modulator and then converted to analog by a digital-to-analog converter (DAC) (not shown) to generate an analog signal 332. The analog signal 332 is then filtered by a block upconverter (BUC) 304 and provided to one port of the diplexer 305. In one embodiment, BUC 304 is in an outdoor unit (ODU). Diplexer 305, operating in a manner well known in the art, provides a transmit signal 332 to ASM 301 for transmission.

In one embodiment, to support its operation, modem 303 includes an intermediate frequency (IF) transceiver 310, which transmits and receives signals at intermediate frequencies, and retrieves data for the digital system. A digital baseband processor 311 processes down-converted digital signals to store parameters, data tables, and other information used by the modem to perform modulation, demodulation, and other functions. Memory 312, a clock management unit 313 for managing clocking of operations of the modem 303, and a power management unit 314 for managing power consumption of the modem 303. management unit). These units operate in a manner well known in the art unless otherwise specified.

In operation, in one embodiment, as one satellite begins to leave the terminal's field of view, the antenna aperture of ASM 301 changes from a single beam configuration to a two beam configuration and interconnects the second beam with the next satellite. Controlled to initiate connection establishment. In one embodiment, the secondary beam is only for locating and connecting to the next satellite and does not transmit a large amount of data, and therefore the gain of the secondary beam relative to the primary beam is lower, thereby reducing the data transmission rate of the satellite terminal ( The impact on data transmission rates can be reduced and potentially minimized.

In one embodiment, two beams are generated simultaneously with a single electronically steered planar antenna to access the satellite, followed by seamless handoff of traffic from the first beam to the second beam, while the first beam and the second beam are pointing to the same satellite, but are accessing satellite carriers on distinct frequencies. An example of this is shown in Figure 4.

Referring to FIG. 4, the host processor 401 generates pointing and tracking information 400 and sends it to the ASM 301 for one or two receive beams. In one embodiment, pointing and tracking information 400 includes theta (e.g., Theta1), phi (e.g., Phi1), frequency (e.g., freq1, freq2), and symbol rate (e.g., SR1) information. This may be in response to signal quality information or metrics, such as a Received Signal Strength Indicator (RSSI) (e.g., RSSI1, RSSI2) or a SINR value (e.g., SINR1, SINR2) associated with the received signal associated with received beams 1 and 2. . In one embodiment, this is a response to physical layer synchronization signals (eg, PLsynch1, PLsynch2) indicating that the antenna beam is tracking a satellite. In one embodiment, signal quality information or metrics and synchronization signals are received from modem 303.

Using beams 1 and 2, the antenna aperture of ASM 301 receives signals from one or two satellites. The received signal is sent to diplexer 305 and then to LNB 306, operating as discussed above. From the LNB 306, the signal is sent to a 2-way power divider 430 that splits the received signal into a tracking receive signal (Rx1) 431 and a tracking receive signal (Rx2) 432. is sent to the divider. In one embodiment, the tracking received signal (Rx1) 431 and the tracking received signal (Rx2) 432 are terminated in an RF tuner within the modem 303 where frequency selection occurs. In this case, the power splitter 430 is a simple power splitter. In another embodiment, the power divider 430 may use a bandpass filter to filter the incoming signal to produce a tracking received signal (Rx1) 431 and a tracking received signal (Rx2) 432. ) operates as These signals are sent to modem 303 and processed as described above.

Although not shown in Figure 4, in one embodiment, a second splitter/power divider is placed in front of LNB 306 and is included to split between Rx1 and Rx2.

In one embodiment, the second beam is generated by an electronically steered planar antenna and is pointed based on an estimate of the new satellite position provided by a two-line element (TLE), which is an object orbiting the Earth for a given point in time. is a list of orbital elements of an Earth-orbiting object, and then an estimate of the second satellite position is improved using modem signal feedback for optimization.

In one embodiment, unequal beam splitting occurs, whereby one antenna has two antennas with different gains (e.g., gains that differ by approximately 10 dB for High-Throughput Satellites (HTS), etc.). producing two beams, so that the original beam maintains data communication and tracks the first satellite, while the second, lower gain beam is used to optimize beam pointing towards the new incoming satellite.

In one embodiment, the antenna used in the above embodiment may be a dual aperture to support simultaneous transmit and receive functions rather than a receive-only aperture, thereby allowing transmission as well as handoff of receive traffic. Provides handoff of traffic.

In one embodiment, handoff of transmitting traffic occurs from the satellite used for receiving traffic to two separate satellites, eg, the transmitting and receiving satellites are not necessarily the same.

The technology disclosed herein includes, but is not limited to, geostationary (GEO), medium earth orbit (MEO), low earth orbit (LEO), certain non-geostationary and geostationary satellite constellations, as well as moving satellites to steer the beam. It can be applied to several spacecraft with tracking performance implemented using an electronically steered antenna system that does not require mechanical components.

For example, in one LEO constellation, a satellite is in the field of view of a ground terminal for a short period of time, such as 4 minutes, and any passing satellite is replaced by another incoming satellite, so there is overlap for satellite connections. LEO satellite positions as a function of time are known via TLE, typically a two-line element, and communicated to a ground terminal during a satellite link. As the moment of satellite handoff approaches, the ground terminal generates a second antenna beam and points that beam in the direction specified by the TLE with respect to the incoming satellite, doing so before the outgoing satellite is no longer in sight; Thereby providing MBB performance (make-before-break capability). In one embodiment, a ground terminal may track and forward user traffic from a first beam pointing to a first LEO satellite while simultaneously acquiring new incoming LEO satellites to the second beam, and then transfer user traffic from the first beam to the second beam. Handoff of traffic is seamlessly managed by the beam and then the first beam is turned off, thereby providing continuous service to the user.

Embodiments of the present invention provide continuous satellite connectivity. In one embodiment, the purpose of beam splitting is to reduce, and potentially eliminate, the amount of connection downtime between satellite handoffs. These hand-offs occur repeatedly as the LEO satellite orbits, improving the user experience by reducing connectivity drops.

Figure 5A is a timing diagram of one embodiment of a process in which one receive beam is split into two receive beams. The original beam (Beam 1) 501 is used for Forward Link data, also known as FL, while the split beam of the split beam period 502, Beam 2, is used to track incoming LEO satellites. . FL refers to signals originating from the Ground Network (GN) (also known as HUB) and terminating at a terminal. In one embodiment, the two beams do not have the same antenna gain. In one embodiment, the second beam, Beam 2, is given sufficient antenna gain so that the terminal Rx modem can use the split beam signal to acquire incoming satellites. Once the incoming satellite is acquired, FL handoff occurs. In one embodiment, the FL data capacity is limited by the received signal strength (e.g., signal-to-noise ratio (SNR)) and is determined by the GN. During the beam splitting period 502, the data capacity will be lower because the traffic bearing beam will have a lower antenna gain than normal, shown as compressed mode in Figure 5A. Compressed mode represents a reduced modulation and coding scheme (MODCOD) (e.g., MCS) due to splitting the beam, i.e., reduced antenna gain, long enough to track and couple incoming satellites. Once the split beam period 502 is complete, the traffic bearing beam (e.g., moving forward Beam 2) may return to full antenna gain.

In one embodiment, the techniques described herein are also extended to a reverse link, RL, connection that is established as soon as the FL is handed off. That is, although FL handoff is discussed above, RL handoff is also caused by antenna duplex capabilities. 5B illustrates an example of transmit (Tx) beam splitting and handoff and corresponding timing diagram. Referring to Figure 5b, Tx beam splitting does not necessarily result in the same satellite or beam as the receive (Rx) beam splitting. However, it could be the very same satellite or beam.

Example of Antenna Embodiment

The disclosed technology can be used with flat panel antennas. An embodiment of such a flat panel antenna is disclosed. A flat panel antenna includes one or more arrays of antenna elements over the antenna aperture. In one embodiment, the antenna element includes liquid crystal cells. In one embodiment, the flat panel antenna is a cylindrically fed antenna that includes matrix drive circuitry to uniquely address and drive each antenna element that is not arranged in rows and columns. In one embodiment, the elements are arranged in a ring.

In one embodiment, the antenna aperture containing one or more arrays of antenna elements is comprised of multiple segments joined together. When joined together, the combination of segments forms closed concentric rings of antenna elements. In one embodiment, the concentric ring is concentric with respect to the antenna feed.

Example of antenna system

In one embodiment, the flat panel antenna is part of a metamaterial antenna system. An embodiment of a metamaterial antenna system for a communication satellite earth station is disclosed. In one embodiment, the antenna system is a satellite earth station (ES) operating on a mobile platform (e.g., air, maritime, land, etc.) operating using Ka-band frequencies or Ku-band frequencies for civil commercial satellite communications. It is a component or subsystem of. It should be noted that embodiments of the antenna system may also be used in earth stations that are not on mobile platforms (eg, fixed or transportable earth stations).

In one embodiment, the antenna system utilizes surface scattering metamaterial technology to shape and steer transmit and receive beams through individual antennas. In one embodiment, the antenna system is an analog system, as opposed to antenna systems that employ digital signal processing to electrically shape and steer the beam (e.g., phased array antennas).

In one embodiment, the antenna system consists of three functional subsystems: (1) a wave guiding structure consisting of a cylindrical wave feed architecture; (2) an array of wave scattering metamaterial unit cells that are part of the antenna element; and (3) a control structure for commanding the formation of a tunable radiation field (beam) from the metamaterial scattering element using holographic principles.

antenna element

Figure 6 illustrates a schematic diagram of one embodiment of a cylindrically fed holographic radial aperture antenna. Referring to Figure 6, the antenna aperture has one or more arrays 601 of antenna elements 603 arranged in a concentric ring around the input feed 602 of the cylindrical feed antenna. In one embodiment, antenna element 603 is a radio frequency (RF) resonator that radiates RF energy. In one embodiment, antenna element 603 has both Rx and Tx iris interleaved and distributed over the entire surface of the antenna aperture. These Rx and Tx iris, or slots, can be in groups of three or more sets with each set individually for a simultaneously controlled band. Examples of such antenna elements with ariris are disclosed in more detail below. It should be noted that the RF resonator disclosed herein can be used in antennas that do not include a cylindrical feed.

In one embodiment, the antenna includes a coaxial feed used to provide a cylindrical wave feed through an input feed 602. In one embodiment, a cylindrical wave feed structure feeds the antenna from a central point with excitation spreading outward in a cylindrical manner from the feed point. In other words, the cylindrical feed antenna generates an outward traveling concentric feed wave. Nevertheless, the shape of the cylindrical feed antenna around the cylindrical feed may be circular, square or of any shape. In another embodiment, a cylindrical feed antenna generates an inward traveling feed wave. In this case, the feed wave most naturally originates from a circular structure.

In one embodiment, the antenna element 603 includes an iris, and the aperture antenna of Figure 6 is shaped using excitation from a cylindrical feed wave to radiate the iris through a tunable liquid crystal (LC) material. It is used to generate the main beam. In one embodiment, the antenna can be excited to radiate a horizontally or vertically polarized electric field at a desired scan angle.

In one embodiment, the antenna element includes a group of patch antennas. This group of patch antennas is equipped with an array of scattering metamaterial elements. In one embodiment, each scattering element of the antenna system includes a lower conductor, a dielectric substrate, and a complementary electric inductive resonator etched from or deposited on the upper conductor. It is part of a unit cell consisting of an upper conductor containing a -capacitive resonator ("complementary electric LC" or "CELC"). As understood by those skilled in the art, LC in the context of CELC refers to inductance-capacitance, as opposed to liquid crystal.

In one embodiment, liquid crystals (LC) are disposed in the gap around the scattering element. This LC is driven by the direct drive embodiment described above. In one embodiment, a liquid crystal is encapsulated in each unit cell, separating the lower conductor associated with the slot from the upper conductor associated with its patch. Liquid crystals have a permittivity that is a function of the orientation of the molecules comprising the liquid crystal, and the orientation of the molecules (and therefore the permittivity) can be controlled by adjusting the bias voltage across the liquid crystal. Taking advantage of this property, in one embodiment, the liquid crystal integrates an on/off switch for the transmission of energy from a guided wave to the CELC. When switched on, the CELC emits electromagnetic waves, electrically like a small dipole antenna. The teachings herein are not limited to those with liquid crystals that operate in a binary fashion with respect to energy transfer.

In one embodiment, the feed shape of this antenna system may be such that the antenna elements are positioned at a forty-five degree (45°) angle to the wave vector in the wave feed. It should be noted that other positions (e.g., 40° angles) may be used. This position of the element allows control of the free space waves received by or transmitted/radiated from the element. In one embodiment, the antenna elements are arranged with inter-element spacing less than the free-space wavelength of the antenna's operating frequency. For example, if there are four scattering elements per wavelength, the elements in a 30 GHz transmit antenna are approximately 2.5 mm (i.e., 1/4 the 10 mm free space wavelength at 30 GHz).

In one embodiment, the two sets of elements are orthogonal to each other and have equal amplitude excitation when controlled to the same tuning state. By rotating +/-45 degrees relative to the feed wave excitation, the desired characteristics can be achieved at once. Rotating one set 0 degrees and the other 90 degrees achieves the vertical goal, but does not achieve the same amplitude excitation goal. 0 degrees and 90 degrees can be used to achieve isolation when feeding an array of antenna elements from two sides into a single structure.

The amount of power radiated from each unit cell is controlled by applying a voltage to the patch (potential across the LC channel) using a controller. Traces for each patch are used to provide voltage to the patch antenna. The voltage is used to tune or detune the capacitance and thus the resonance frequency of the individual elements to cause beam forming. The required voltage depends on the liquid crystal mixture used. The voltage tuning properties of liquid crystal mixtures are mainly described by the threshold voltage above which the liquid crystal begins to be affected by voltage and saturation voltage, above which an increase in voltage does not cause significant tuning in the liquid crystal. These two characteristic parameters can vary for different liquid crystal mixtures.

In one embodiment, as discussed above, a matrix drive applies a voltage to the patch to drive each cell individually from all other cells (direct drive) without having a separate connection for each cell. It is used for authorization. Because of the high density of elements, matrix drives are an efficient way to process each cell individually.

In one embodiment, the control structure of the antenna system has two main components: an antenna array controller containing the drive electronics for the antenna system (of the surface scattering antenna elements as described herein); Below the wave scattering structure, while matrix drive switching arrays are interspersed throughout the radiating RF array in a way that does not disturb the radiation. In one embodiment, the drive electronics for the antenna system include a commercial off-the-shelf LCD for use in commercial television equipment that adjusts the bias voltage for each scattering element by adjusting the amplitude or duty cycle of the AC bias signal for that element. Equipped with a control device.

In one embodiment, the antenna array controller also includes a microprocessor that executes software. The control structure may integrate sensors (e.g., GPS receiver, 3-axis compass, 3-axis accelerometer, 3-axis gyro, 3-axis magnetometer, etc.) to provide location and orientation information to the processor. Position and orientation information may be provided to the processor by other systems of the earth station and/or other systems that may not be part of the antenna system.

In particular, the antenna array controller controls which elements are turned off and which elements are turned on, and at what phase and amplitude level at the operating frequency. The element is selectively detuned for frequency operation by applying a voltage.

For transmission, the controller supplies an array of voltage signals to the RF patch to create a modulation or control pattern. Control patterns allow elements to be tuned to different states. In one embodiment, multi-state control is used to turn various elements on and off to various levels and uses a sinusoidal control pattern as opposed to a square wave (i.e., sinusoidal gray shade modulation pattern). pattern). In one embodiment, rather than some elements radiating and some not, some elements radiate more strongly than others. Variable radiation is achieved by applying a specific voltage level, which adjusts the liquid crystal dielectric constant for a varying amount, thereby variably detuning the elements and causing some elements to radiate more than others.

The generation of a focused beam by a metamaterial array of elements can be explained by the phenomena of constructive and destructive interference. Individual electromagnetic waves add up if they are in the same phase when they meet in free space (constructive interference), and if they are in opposite phases when they meet in free space, they cancel each other out (destructive interference). If the slots of a slotted antenna are arranged so that each successive slot is located at a different distance from the excitation point of the guided wave, the scattered wave from that element will have a different phase from the scattered wave from the previous slot. will have If the slots are spaced apart by 1/4 the guided wavelength, each slot will scatter waves with a 1/4 phase lag from the previous slot.

Using an array, the number of patterns of constructive and destructive interference that can be generated can be increased, so the beam is directed at a predetermined angle of plus or minus 90 degrees from the bore sight of the antenna array using the principles of holography. It can theoretically be pointed in a direction. Therefore, by controlling which metamaterial unit cells are turned on or off (i.e., by changing the pattern of which cells are turned on and which cells are turned off), different patterns of constructive and destructive interference can be created. can occur, and the antenna can change the direction of the main beam. The time required to turn a unit cell on and off dictates the speed at which the beam can be switched from one position to another.

In one embodiment, the antenna system generates one steerable beam for the uplink antenna and one steerable beam for the downlink antenna. In one embodiment, the antenna system uses metamaterial technology to receive the beam, decode signals from the satellite, and form a transmit beam that is directed toward the satellite. In one embodiment, the antenna system is an analog system, as opposed to an antenna system that employs digital signal processing to electrically shape and steer the beam (e.g., a phased array antenna). In one embodiment, the antenna system is considered a “surface” antenna, which is planar and relatively low profile, especially when compared to conventional satellite dish receivers.

Figure 7 illustrates a perspective view of one row of antenna elements including a ground plane and a reconfigurable resonator layer. Reconfigurable resonator layer 1230 includes an array of tunable slots (1210). The array of tunable slots 1210 can be configured to point the antenna in a desired direction. Each tunable slot can be tuned/adjusted by changing the voltage across the liquid crystal.

A control module, or controller 1280, is coupled to the reconfigurable resonator layer 1230 to modulate the array of tunable slots 1210 by varying the voltage across the liquid crystal in FIG. 8A. Control module 1280 may include a Field Programmable Gate Array (“FPGA”), microprocessor, controller, System-on-a-Chip (SoC), or other processing logic. In one embodiment, control module 1280 includes logic circuitry (e.g., a multiplexer) to drive an array of tunable slots 1210. In one embodiment, control module 1280 receives data containing specifications for causing a holographic diffraction pattern to be driven on an array of tunable slots 1210. The holographic diffraction pattern may be generated in response to the spatial relationship between the antenna and the satellite so that the holographic diffraction pattern steers the downlink beam (and uplink beam if the antenna system is transmitting) in the appropriate direction for communication. . Although not shown in each figure, a control module similar to control module 1280 may drive each array of tunable slots depicted in the figures of this disclosure.

Radio Frequency (“RF”) holography is also possible using similar techniques in which a desired RF beam can be generated when an RF reference beam encounters an RF holographic diffraction pattern. For satellite communications, the reference beam is in the form of a feed wave, such as feed wave 1205 (approximately 20 GHz in some embodiments). To convert the feed wave into a radiated beam (for transmission or reception purposes), an interference pattern is calculated between the desired RF beam (object beam) and the feed wave (reference beam). do. The interference pattern is driven on the array of tunable slots 1210 as a diffraction pattern such that the feed wave is “steered” into the desired RF beam (with the desired shape and direction). That is, the feed wave encountering the holographic diffraction pattern “reconstructs” the target beam, which is shaped according to the design requirements of the communication system. The holographic diffraction pattern includes the excitation of each element and is expressed as a wave equation in the waveguide: and as the wave equation for the outflow wave: Having, It is calculated by

FIG. 8A illustrates one embodiment of a tunable resonator/slot 1210. Tunable slot 1210 includes an iris/slot 1212, a radiating patch 1211, and a liquid crystal 1213 disposed between iris 1212 and patch 1211. In one embodiment, radiating patch 1211 is co-located with iris 1212.

Figure 8B illustrates a cross-sectional view of one embodiment of a physical antenna aperture. The antenna aperture includes a ground plane 1245 and a metal layer 1236 in the iris layer 1233 included in the reconfigurable resonator layer 1230. In one embodiment, the antenna aperture of FIG. 8B includes a plurality of tunable resonators/slots 1210 of FIG. 8A. Iris/slot 1212 is defined by openings in metal layer 1236. The feed wave, such as feed wave 1205 in FIG. 8A, may have a microwave frequency compatible with a satellite communication channel. The feed wave propagates between ground plane 1245 and resonator layer 1230.

Reconfigurable resonator layer 1230 also includes a gasket layer 1232 and a patch layer 1231. Gasket layer 1232 is disposed between patch layer 1231 and iris layer 1233. It should be noted that in one embodiment, a spacer may replace gasket layer 1322. In one embodiment, iris layer 1233 is a printed circuit board (“PCB”) that includes a layer of copper as metal layer 1236. In one embodiment, iris layer 1233 is glass. Iris layer 1233 may be a different type of substrate.

Openings may be etched in the copper layer to form slots 1212. In one embodiment, iris layer 1233 is conductively bonded to other structures (e.g., waveguides) of FIG. 8B by a conductive bonding layer. In one embodiment, the iris layer is not conductively bonded by a conductive bonding layer but is instead interfaced with a non-conducting bonding layer.

The patch layer 1231 may also be a PCB containing metal as the radiating patch 1121. In one embodiment, gasket layer 1232 includes spacers 1239 that provide mechanical standoff to define the dimensions between metal layer 1236 and patch 1211. In one embodiment, the spacer is 75 microns, but other sizes may be used (eg, 3-200 mm). As noted above, in one embodiment, the antenna aperture of FIG. 8B may be configured such that, for example, tunable resonator/slot 1210 includes patch 1211, liquid crystal 1213, and iris 1212 of FIG. 8A. Contains multiple tunable resonators/slots, such as: The chamber for liquid crystal 1213 is defined by spacer 1239, iris layer 1233, and metal layer 1236. When the chamber is filled with liquid crystal, patch layer 1231 may be deposited on spacer 1239 to seal the liquid crystal within resonator layer 1230.

The voltage between the patch layer 1231 and the iris layer 1233 may be modulated to tune the liquid crystal in the gap between the patch and the slot (eg, tunable resonator/slot 1210). Adjusting the voltage across liquid crystal 1213 changes the capacitance of the slot (e.g., tunable resonator/slot 1210). Accordingly, the reactance of a slot (e.g., tunable resonator/slot 1210) can be changed by changing the capacitance. The resonant frequency of slot 1210 can also be calculated using the equation varies depending on, where: is the resonant frequency of the slot 1210, L and C are the inductance and capacitance of the slot 1210, respectively. The resonant frequency of the slot 1210 affects the energy radiated from the feed wave 1205 propagating through the waveguide. For example, if the feed wave 1205 is 20 GHz, the resonant frequency of the slot 1210 can be adjusted to 17 GHz (by changing the capacitance) such that the slot 1210 couples substantially no energy from the feed wave 1205. . Alternatively, the resonant frequency of slot 1210 can be adjusted to 20 GHz such that slot 1210 couples energy from feed wave 1205 and radiates that energy into free space. Although the given example is a binary (completely radiating or not radiating at all), full gray scale control of reactance, the resonant frequency of slot 1210 therefore has voltage variance over a multi-value range. It is possible. Accordingly, the energy radiated from each slot 1210 can be finely controlled such that a detailed holographic diffraction pattern can be formed by the array of tunable slots.

In one embodiment, tunable slots in a row are spaced from each other by λ/5. Other spacings may be used. In one embodiment, each tunable slot in a row is offset from the nearest tunable slot in the adjacent row by λ/2, so that commonly oriented tunable slots in other rows are offset by λ/4. , other spaces are possible (e.g., λ/5, λ/6.3). In another embodiment, each tunable slot in a row is offset from the nearest tunable slot in the adjacent row by λ/3.

An embodiment is filed on November 21, 2014 and titled "Dynamic Polarization and Coupling Control from a Steerable Cylindrically Fed Holographic Antenna" U.S. Patent Application No. 14/550,178, and U.S. Patent Application No. 14, filed January 30, 2015, entitled "Ridged Waveguide Feed Structures for Reconfigurable Antenna." /Use reconfigurable metamaterial technology, such as No. 610,502.

9A-9D illustrate one embodiment of multiple layers for creating a slotted array. The antenna array includes antenna elements positioned in a ring, such as the example ring shown in FIG. 1A. It should be noted that in this example, the antenna array has two different types of antenna elements used for two different types of frequency bands.

Figure 9A illustrates a portion of the first iris board layer with positions corresponding to slots. Referring to Figure 9A, the circles are open areas/slots of metallization on the bottom side of the iris substrate and are for controlling the coupling of elements to the feed (feed wave). It should be noted that this layer is an optional layer and will not be used in all designs. Figure 9B illustrates a portion of the second iris board layer including slots. Figure 9C illustrates a patch spanning a portion of the second iris board layer. Figure 9D illustrates a top view of a portion of a slotted array.

Figure 10 illustrates a side view of one embodiment of a cylindrically fed antenna structure. The antenna uses a double layer feed structure (i.e., two layers of the feed structure) to generate an inwardly traveling wave. In one embodiment, the antenna includes a circular outer shape, but this is not required. That is, non-circular inward traveling structures can be used. In one embodiment, the antenna structure of FIG. 10 is described in, e.g., U.S. Publication No. 1, "Dynamic Polarization and Coupling Control from a Steerable Cylindrical Feed Holographic Antenna," filed on November 21, 2014. It includes a coaxial feed, as described in 2015/0236412.

Referring to Figure 10, coaxial pin 1601 is used to excite the field to the lower level of the antenna. In one embodiment, coaxial pin 1601 is a readily available 50Ω coaxial pin. Coaxial pin 1601 is coupled (e.g., bolted) to the bottom of the antenna structure conducting ground plane 1602.

Apart from the conductive ground plane 1602, there is an interstitial conductor 1603, which is an internal conductor. In one embodiment, the conducting ground plane 1602 and the interstitial conductor 1603 are parallel to each other. In one embodiment, the distance between ground plane 1602 and insertion conductor 1603 is 0.1-0.15". In another embodiment, this distance may be λ/2, where λ is the value of the traveling wave at the operating frequency. It is a wavelength.

Ground plane 1602 is separated from insertion conductor 1603 via spacer 1604. In one embodiment, spacer 1604 is foam or an air-like spacer. In one embodiment, spacer 1604 includes a plastic spacer.

On top of the insertion conductor 1603 is a dielectric layer 1605. In one embodiment, dielectric layer 1605 is plastic. The purpose of the dielectric layer 1605 is to slow the traveling wave relative to the free space velocity. In one embodiment, dielectric layer 1605 slows traveling waves by as much as 30% compared to free space. In one embodiment, a range of refractive indices suitable for beam forming is 1.2-1.8, where free space by definition has a refractive index equal to 1. Other dielectric spacer materials, such as plastics, may be used to achieve this effect. Materials other than plastic may be used as long as they achieve the desired wave retardation effect. Alternatively, materials with distributed structures can be used as dielectric 1605, such as periodic sub-wavelength metallic structures that can be defined by machining or lithography.

RF-array 1606 is on top of dielectric 1605. In one embodiment, the distance between insertion conductor 1603 and RF-array 1606 is 0.1-0.15". In another embodiment, this distance is can be, where is the effective wavelength of the medium at the design frequency.

The antenna includes sides 1607 and 1608. Sides 1607 and 1608 allow the traveling wave feed from coaxial pin 1601 to propagate through reflection from the area below insertion conductor 1603 (spacer layer) to the area above insertion conductor 1603 (dielectric layer). It is angled to prevent damage. In one embodiment, the angle of sides 1607 and 1608 is a 45° angle. In an alternative embodiment, sides 1607 and 1608 may be replaced with continuous radii to achieve reflection. Figure 10 shows an angled side with an angle of 45 degrees, other angles can be used to achieve signal transmission from lower level feed to upper level feed. That is, considering that the effective wavelength in the lower feed will generally be different than the upper feed, some deviation from the ideal 45° angle can be used to aid transmission from the lower to upper feed levels. For example, in another embodiment, the 45° angle is replaced by a single step. The step on one end of the antenna goes around the dielectric layer, intercalating conductor, and spacer layer. The same two steps are at the other end of these floors.

In operation, when a feed wave is supplied from the coaxial pin 1601, the wave propagates concentrically oriented from the coaxial pin 1601 in the area between the ground plane 1602 and the insertion conductor 1603. The concentric outgoing wave is reflected by sides 1607 and 1608 and propagates inward in the area between insertion conductor 1603 and RF array 1606. Reflection from the edge of the circular perimeter causes the wave to remain in phase (i.e., it is in-phase reflection). The traveling wave is slowed down by the dielectric layer 1605. At this point, the traveling wave begins to interact and excite elements in the RF array 1606 to achieve the desired scattering.

To terminate the traveling wave, an end 1609 is included in the antenna at its geometric center. In one embodiment, end 1609 has a pin end (eg, a 50Ω pin). In another embodiment, terminal 1609 is provided with an RF absorber that terminates unused energy to prevent reflection of unused energy back through the feed structure of the antenna. These may be used on top of the RF array 1606.

Figure 11 illustrates another embodiment of an antenna system with emanating waves. Referring to Figure 11, two ground planes 1610 and 1611 are substantially parallel to each other with a dielectric layer 1612 (eg, a plastic layer, etc.) between the ground planes. An RF absorber 1619 (e.g., a resistor) couples the two ground planes 1610 and 1611 together. A coaxial pin 1615 (e.g. 50Ω) is supplied to the antenna. RF array 1616 is on top of dielectric layer 1612 and ground plane 1611.

In operation, the feed wave is fed through the coaxial pin 1615 and travels concentrically outward and interacts with elements of the RF array 1616.

The cylindrical feed in both antennas of Figures 10 and 11 improves the service angle of the antennas. Instead of the antenna system having a service angle of plus or minus 45 degrees azimuth (±45°Az) and plus or minus 25 degrees elevation (±25°El), in one embodiment, the antenna system has a service angle of plus or minus 45 degrees azimuth (±45°Az), in one embodiment, the antenna system has a service angle of plus or minus 45 degrees azimuth (±45°Az) and plus or minus 25 degrees elevation (±25°El). It has a service angle of degrees (75°). As with any beamforming antenna composed of many individual radiators, the overall antenna gain depends on the gains of the component elements, which themselves are angle-dependent. When using a common radiating element, the overall antenna gain decreases as the beam is directed further away from the bore site. At 75 degrees out of the bore site, a significant gain drop of approximately 6dB is expected.

Embodiments of antennas with cylindrical feeds solve one or more problems. They dramatically simplify the feed structure compared to antennas fed into a corporate divider network, reducing the overall required antenna and antenna feed volume; Reduced sensitivity to manufacturing and control errors by maintaining high beam performance with coarser controls (extends to fully binary controls); imparting a more advantageous side lobe pattern compared to rectilinear feeds since cylindrically oriented feed waves result in spatially divergent side lobes in the far field; and allowing polarization to be dynamic, including allowing left circular polarization, right circular polarization, and linear polarization without requiring a polarizer.

Array of wave scattering elements

RF array 1606 in FIG. 10 and RF array 1616 in FIG. 11 include a wave scattering subsystem that includes a group of patch antennas (i.e., scatterers) that act as radiators. Includes. This group of patch antennas is equipped with an array of scattering metamaterial elements.

In one embodiment, each scattering element of the antenna system includes a lower conductor, a dielectric substrate, and a complementary electric inductive resonator etched from or deposited on the upper conductor. It is part of a unit cell consisting of an upper conductor containing a -capacitive resonator ("complementary electric LC" or "CELC").

In one embodiment, liquid crystals (LC) are injected into the gap around the scattering element. A liquid crystal is encapsulated in each unit cell and separates the lower conductor associated with the slot from the upper conductor associated with the patch. Liquid crystals have a dielectric constant that is a function of the orientation of the molecules comprising the liquid crystal, and the orientation of the molecules (and thus the dielectric constant) can be controlled by adjusting the bias voltage across the liquid crystal. Using this property, the liquid crystal acts as an on/off switch to transmit energy from guided waves to the CELC. When switched on, the CELC emits electromagnetic waves, electrically equivalent to a small dipole antenna.

Controlling the thickness of the LC increases the beam switching speed. A 50 percent (50%) reduction in the gap between the bottom and top conductors (thickness of the liquid crystal) results in a four-fold increase in speed. In another embodiment, the thickness of the liquid crystal results in a beam switching speed of approximately 14 milliseconds (14 ms). In one embodiment, the LC is doped in a manner known in the art to improve responsiveness to meet the 7 millisecond (7ms) requirement.

The CELC element responds to a magnetic field applied parallel to the plane of the CELC element and perpendicular to the CELC gap complement. When voltage is applied to the liquid crystal in the metamaterial scattering unit cell, the magnetic field component of the guided wave induces magnetic excitation of the CELC, eventually generating an electromagnetic wave at the same frequency as the guided wave.

The phase of the electromagnetic wave generated by a single CELC can be selected by the position of the CELC on the vector of the guided wave. Each cell generates a wave in phase with the guided wave parallel to the CELC. Since the CELC is smaller than the wavelength, the output wave has the same phase as the guided wave as it passes below the CELC.

In one embodiment, the cylindrical feed geometry of this antenna system allows the CELC element to be positioned at a forty-five degree (45°) angle to the vector of the wave in the wave feed. This position of the element allows control of the polarization of the free space waves generated from or received by the element. In one embodiment, the CELC is arranged with inter-element spacing less than the free space wavelength of the antenna's operating frequency. For example, if there are four scattering elements per wavelength, the elements in a 30 GHz transmit antenna are approximately 2.5 mm (i.e., 1/4 the 10 mm free space wavelength at 30 GHz).

In one embodiment, the CELC is implemented with a patch antenna comprising two patches co-located across a slot with a liquid crystal between them. In this regard, the metamaterial antenna acts like a slotted (scattering) wave guide. According to slotted waveguides, the phase of the output wave depends on the position of the slot with respect to the guided wave.

cell placement

In one embodiment, the antenna elements are disposed on the cylindrical feed antenna aperture in a manner to allow a systematic matrix drive circuit. The arrangement of cells includes the arrangement of transistors for driving the matrix. 12 illustrates one embodiment of the arrangement of a matrix drive circuit for antenna elements. Referring to FIG. 12, the row controller 1701 is coupled to the transistors 1711 and 1712 via row select signals (Row1 and Row2), respectively, and the column controller 1702 is connected to the transistors 1711 and 1712. is coupled to the transistors 1711 and 1712 via a column select signal (Colum1). Transistor 1711 is also coupled to antenna element 1721 via a connection to patch 1723, while transistor 1712 is coupled to antenna element 1722 via a connection to patch 1732.

In an initial approach to realize a matrix drive circuit on a cylindrical feed antenna with unit cells arranged in a non-regular grid, two steps are performed. In the first step, the cells are placed on a concentric ring, and each cell is connected to a transistor that is placed next to the cell and acts as a switch to drive each cell individually. In the second step, a matrix drive circuit is built to connect every transistor with a unique address as required by the matrix drive approach. Matrix drive circuits are built by row and column traces (similar to LCDs), but because the cells are placed in a ring, there is no systematic way to assign a unique address to each transistor. This mapping problem results in very complex circuitry to encompass all the transistors and a significant increase in the number of physical traces to achieve routing. Because of the high density of cells, these traces interfere with the RF performance of the antenna due to coupling effects. Additionally, due to the complexity and high packing density of the traces, routing of the traces cannot be achieved by commercially available layout tools.

In one embodiment, the matrix drive circuit is predefined before the cells and transistors are placed. This ensures the minimum number of traces needed to drive every cell with each unique address. This strategy substantially improves the RF performance of the antenna by reducing the complexity of the drive circuit and simplifying routing.

In particular, in one approach, in a first step, cells are placed on a regular rectangular grid consisting of rows and columns that describe each cell's unique address. In the second step, cells are grouped and transformed into concentric circles while maintaining their addresses and associations with rows and columns as defined in the first step. The goal of this transformation is not only to place cells on rings, but also to keep the distance between cells and the distance between rings constant over the entire aperture surface. To achieve this goal, there are several ways to group cells.

In one embodiment, a TFT package is used to enable placement and unique addressing of matrix drives. Figure 13 illustrates one embodiment of a TFT package. Referring to Figure 13, a TFT with input and output ports and a hold capacitor 1803 are shown. To connect the TFTs together using rows and columns, there are two input ports connected to trace 1801 and two output ports connected to trace 1802. In one embodiment, the row and column traces intersect at a 90° angle to reduce and potentially minimize coupling between the row and column traces. In one embodiment, the row and column traces are on different layers.

Example of simultaneous transmission and reception (Full Duplex) communication system

In another embodiment, the combined antenna aperture is used in a full duplex communication system. Figure 14 is a block diagram of an embodiment of a communication system with simultaneous transmit and receive paths. Although only one transmit path and one receive path are shown, the communication system may include one or more transmit paths and/or one or more receive paths.

Referring to FIG. 14, antenna 1401 includes two spatially interleaved antenna arrays that are independently operable to simultaneously transmit and receive at different frequencies, as described above. In one embodiment, antenna 1401 is connected to a diplexer 1445. Coupling may be achieved by one or more feeding networks. In one embodiment, for a radial feed antenna, diplexer 1445 combines the two signals, and the connection between antenna 1401 and diplexer 1445 carries both frequencies. It is a single broad-band feeding network that can

The diplexer 1445 is connected to a low noise block down converter (LNBs) 1427, which provides a noise filtering function and a down conversion and amplification function in a manner known in the art. down conversion and amplification function). In one embodiment, LNB 1427 is in an outdoor unit (ODU). In another embodiment, LNB 1427 is integrated into the antenna device. LNB 1427 is coupled to modem 1460, which is coupled to computing system 1440 (e.g., computer system, modem, etc.).

Modem 1460 includes an analog-to-digital converter (ADC) 1422 coupled to LNB 1427 to convert the received signal output from diplexer 1445 into digital format. do. Once converted to digital format, the signal is demodulated by demodulator 1423 and decoded by decoder 1424 to obtain encoded data on the received wave. The decoded data is then transmitted to controller 1425, which transmits it to computing system 1440.

Modem 1460 also includes an encoder 1430 that encodes data to be transmitted from computing system 1440. The encoded data is modulated by a modulator 1431 and then converted to analog by a digital-to-analog converter (DAC) 1432. The analog signal is then filtered by a BUC (up-convert and high pass amplifier) 1433 and provided to one port of the diplexer 1445. In one embodiment, BUC 1433 is in an outdoor unit (ODU).

Diplexer 1445, operating in a manner known in the art, provides a transmit signal to antenna 1401 for transmission. Controller 1450 controls antenna 1401 and includes two arrays of antenna elements on a single combined physical aperture. The communication system may be modified to include the combiner/arbiter described above. In this case, the combiner/coordinator is after the modem but before the BUC and LNB. It should be noted that the simultaneous transmit and receive communication system shown in FIG. 14 has numerous applications including, but not limited to, Internet communication, vehicle communication (including software updating), and the like. There are a number of example embodiments disclosed herein.

Example 1 includes generating a first beam with a single electronically steered flat-panel antenna to track a first satellite; generating a first beam to track a first satellite while simultaneously generating a second beam to track a second satellite with a single electronically steered flat-panel antenna; and handing off traffic from the first satellite to the second satellite.

Example 2 is the method of Example 1, which can optionally include handing off the traffic is performed seamlessly such that the connection is maintained throughout the transition from the first satellite to the second satellite.

Example 3 may optionally include generating a second beam to acquire a signal from a second satellite while generating the first beam prior to generating the second beam to track the second satellite. This is method 1.

Example 4 shows first and second sets of radio frequencies (RF) on the antenna aperture of a flat-panel antenna that is electronically steered to generate respective first and second beams to point to different carrier frequencies. ) The method of Example 3 may optionally include generating first and second patterns for application to radiating antenna elements, wherein the first and second sets of RF radiating antenna elements are different.

Example 5 is the method of example 4, where the first and second sets of RF radiating antenna elements can optionally include having different numbers of RF radiating antenna elements.

Example 6 is the method of Example 4, which can optionally include RF radiating antenna elements of the first and second sets of RF radiating antenna elements being randomly distributed over the antenna aperture.

Example 7 is wherein the first and second sets of RF radiation antenna elements are in a ring around a central feed for the wave, furthermore, each ring of the first set of RF radiation antenna elements is configured to emit RF radiation of the second set of RF radiation antenna elements. The method of Example 4 can optionally include what is between the rings of antenna elements.

Example 8 is wherein the first and second sets of RF radiating antenna elements are in a ring around a central feed to the wave, and the first set of RF radiating antenna elements is in a ring about a central feed relative to the ring of the second set of RF radiating antenna elements. This is the method of Example 4 that can selectively include those in the ring closest to .

Example 9 is the method of Example 3, which can optionally include the second beam pointing to the predicted location of the second satellite.

Example 10 is the method of Example 1 which can optionally include that the predicted position is based on a commanded 2-line element (TLE).

Example 11 shows that generating the first and second beams have different antenna gains, and when the second beam is used to acquire a signal from a second satellite, the gain for the second beam is greater than the gain for the first beam. This is the method of Example 1, which can optionally include a low value.

Example 12 is the method of Example 3 that can optionally include a second beam being wider than the first beam when used to acquire a signal from a second satellite.

Example 13 includes operating an electronically steered flat-panel antenna in a single beam configuration, prior to generating a first beam to track a first satellite, wherein the electronically steered flat-panel antenna generates a single beam. generating a third beam to track the second satellite using a first set of RF radiation antenna elements on the antenna aperture of the electronically steered flat-panel antenna, the first set of RF radiation The antenna element includes an RF radiating element of a second set of RF radiating elements on the antenna aperture for generating the first beam and an RF radiating element of a third set of RF radiating elements on the antenna aperture for generating the second beam. to do, step; and determining to switch the electronically steered flat-panel antenna to a two-beam configuration in which the electronically steered flat-panel antenna generates first and second beams. It's a method.

Example 14 is the method of example 13, wherein the first set of RF radiating antenna elements can optionally include comprising second and third sets of RF radiating elements.

Example 15 is an antenna for use in satellite communications, the antenna comprising: an electronically steered flat-panel antenna aperture having a plurality of electronically controlled radio frequency (RF) radiating antenna elements; and controlling the antenna aperture to generate a first beam with the antenna aperture to track the first satellite, and simultaneously opening the antenna to track the second satellite while generating the first beam to track the first satellite. and one or more processors coupled to the antenna aperture to generate a second beam in a spherical surface and to hand off traffic from the first satellite to the second satellite.

Example 16 may optionally include one or more processors operable to seamlessly hand off traffic between the first satellite and the second satellite such that the connection is maintained throughout the transition from the first satellite to the second satellite. It's a method.

Example 17 provides an antenna aperture to generate a second beam to acquire a signal from a second satellite while one or more processors generate the first beam prior to generating the second beam to track the second satellite. The method of Example 15 can optionally include controlling .

Example 18 provides one or more processors of respective first and second sets of radio frequency (RF) radiating antenna elements of an antenna aperture to generate respective first and second beams to point at different carrier frequencies. The method of Example 17 operable to generate first and second patterns for application to the first and second sets, wherein the RF radiating antenna elements of the first and second sets can optionally include different ones.

Example 19 is the method of example 18, where the first and second sets of RF radiating antenna elements can optionally include having different numbers of RF radiating antenna elements.

Example 20 is wherein the first and second sets of RF radiation antenna elements are in a ring around a central feed for the wave, wherein each ring of the first set of RF radiation antenna elements is configured to emit RF radiation of the second set of RF radiation antenna elements. The method of Example 18 can optionally be included between the rings of antenna elements.

Example 21 provides the first and second sets of RF radiating antenna elements in a ring about a central feed to the wave, wherein the first set of RF radiating antenna elements has a central feed relative to the ring of the second set of RF radiating antenna elements. This is the method of Example 18 that can selectively include those in the ring closest to .

Example 22 is the method of Example 15, which can optionally include the second beam pointing to the predicted location of the second satellite.

Example 23 is the method of Example 22, which can optionally include that the predicted position is based on a commanded two-line element (TLE).

Example 24 optionally provides that the first and second beams have different antenna gains, and the gain for the second beam is lower than the gain for the first beam when the second beam is used to acquire a signal from a second satellite. This is the method of Example 17 that can be included.

Example 25 is the method of Example 15 that can optionally include a second beam being wider than the first beam when used to acquire a signal from a second satellite.

Some portions of the above detailed description are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and expressions are the means used by those skilled in the art of data processing to most effectively convey the content of their work to others skilled in the art. Here, an algorithm is generally conceived of as a coherent sequence of steps that lead to a desired result. This step requires physical manipulation of physical quantities. Typically, but not necessarily, these quantities take the form of electrical or magnetic signals that can be stored, transferred, combined, compared and otherwise manipulated. It has sometimes proven convenient to refer to these signals as bits, values, elements, symbols, letters, terms, numbers, etc., primarily for reasons of general use.

However, it should be borne in mind that all these terms and similar terms must all relate to the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless explicitly stated otherwise in the following discussion, throughout the description, discussions utilizing terms such as "processing" or "computing" or "calculation" or "determination" or "displaying" refer to the registers and memory of a computer system. A computer system or similar electronic computing device that manipulates and converts data represented as physical (electronic) quantities within a computer system or register or other such information storage, transmission or display device into other data similarly represented as physical quantities within a computer system or similar electronic computing device. It is recognized that it refers to the actions and processes of the device.

The invention also relates to a device for performing the operations herein. The device may be specially configured for the required purpose, or may comprise a general-purpose computer that is selectively activated or reconfigured by a computer program stored on the computer. These computer programs may be stored on any type of disk, ROM, RAM, EPROM, EEPROM, magnetic or optical card, or electronic instructions, including, but not limited to, floppy disks, optical disks, CD-ROMs, and magneto-optical disks. and may be stored in a computer-readable storage medium, such as any form of media coupled to a computer system bus, respectively.

The algorithms and displays presented herein are not inherently related to any particular computer or other device. A variety of general purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct more specialized equipment to perform the necessary method steps. The necessary structures for these various systems will appear from the description below. Moreover, the invention is not described with reference to any specific programming language. It will be understood that various programming languages may be used to implement the teachings of the invention as described herein.

Machine-readable media includes some mechanism for storing or transmitting information in a form readable by a machine (eg, computer). For example, machine-readable media may include ROM; RAM; magnetic disk storage media; optical storage media; flash memory device; Includes etc.

While many variations and modifications of the invention will no doubt occur to those skilled in the art after reading the foregoing description, it should be understood that any specific embodiments shown and described by way of example are not intended to be limiting. Accordingly, references to details of various embodiments are not intended to limit the scope of the claims, which themselves recite only those features considered essential to the invention.

Claims (25)

A method for use in satellite communications, the method being:
generating a first beam with a single electronically steered flat-panel antenna to track a first satellite;
generating a second beam with a single electronically steered flat-panel antenna to track a second satellite while simultaneously generating a first beam to track a first satellite, wherein the direction is electronically controlled by a single electronically steered flat-panel antenna that electronically scans in two dimensions; and
A method for use in satellite communication, comprising: handing off traffic from a first satellite to a second satellite. According to paragraph 1,
A method for use in satellite communications, wherein the step of handing off traffic is performed seamlessly so that the connection is maintained throughout the transition from the first satellite to the second satellite. According to paragraph 1,
Prior to generating the second beam to track the second satellite, the satellite communication method further includes the step of generating a second beam to acquire a signal from the second satellite while generating the first beam. How to use it. According to paragraph 3,
First and second sets of radio frequency (RF) radiating antennas, respectively, on an antenna aperture of a flat-panel antenna electronically steered to generate respective first and second beams to point carriers at different frequencies. A method for use in satellite communications, further comprising generating first and second patterns for application to the elements, wherein the first and second sets of RF radiating antenna elements are different. According to paragraph 4,
A method for use in satellite communications, wherein the first and second sets of RF radiating antenna elements have different numbers of RF radiating antenna elements. According to paragraph 4,
A method for use in satellite communications, wherein each RF radiating antenna element of the first and second sets of RF radiating antenna elements is randomly distributed over the antenna aperture. According to paragraph 4,
The first and second sets of RF radiating antenna elements are in a ring around a central feed for the wave, furthermore each ring of the first set of RF radiating antenna elements is positioned at a ring of the RF radiating antenna elements of the second set of RF radiating antenna elements. A method for use in satellite communications, characterized in that between rings. According to paragraph 4,
The first and second sets of RF radiating antenna elements are in a ring around a central feed for the wave, the first set of RF radiating antenna elements being closest to the central feed compared to the ring of second set of RF radiating antenna elements. A method for use in satellite communications, characterized in that it is in a ring. According to paragraph 3,
A method for use in satellite communications, wherein the second beam points to the predicted location of the second satellite. According to clause 9,
A method for use in satellite communications, wherein the predicted position is based on a commanded two-line element (TLE). According to paragraph 3,
characterized in that the step of generating the first and second beams have different antenna gains, and when the second beam is used to acquire a signal from the second satellite, the gain for the second beam is lower than the gain for the first beam. A method for use in satellite communications. According to paragraph 3,
A method for use in satellite communications, wherein the second beam is wider than the first beam when used to acquire signals from the second satellite. According to paragraph 1,
Prior to generating a first beam to track a first satellite,
operating the electronically steered flat-panel antenna in a single beam configuration wherein the electronically steered flat-panel antenna generates a single beam, wherein operating the electronically steered flat-panel antenna comprises: - generating a third beam to track a second satellite using a first set of RF radiation antenna elements on the antenna aperture of the panel antenna, wherein the first set of RF radiation antenna elements generate the first beam. comprising each RF radiating element of the second set of RF radiating elements on the antenna aperture for generating a second beam and each RF radiating element of the third set of RF radiating elements for generating a second beam; and
determining to switch the electronically steered flat-panel antenna to a two-beam configuration in which the electronically steered flat-panel antenna generates first and second beams. How to use it. According to clause 13,
A method for use in satellite communications, wherein the first set of RF radiating antenna elements includes second and third sets of RF radiating elements. An antenna for use in satellite communications, comprising:
An electronically steered flat-panel antenna aperture having a plurality of electronically controlled radio frequency (RF) radiating antenna elements; and
Controlling the antenna aperture to generate a first beam with the antenna aperture to track a first satellite, and simultaneously controlling the antenna aperture to track a second satellite while generating the first beam to track the first satellite. one or more processors coupled to the antenna aperture to generate a second beam and to hand off traffic from the first satellite to the second satellite,
An antenna for use in satellite communications, wherein the direction of the first beam and the second beam is electronically controlled by a single electronically steered flat-panel antenna that scans electronically in two dimensions. According to clause 15,
An antenna for use in satellite communications, wherein one or more processors are operable to seamlessly hand off traffic between a first satellite and a second satellite such that the connection is maintained throughout the transition from the first satellite to the second satellite. According to clause 15,
Prior to generating the second beam to track the second satellite, the at least one processor controls the antenna aperture to generate the second beam to acquire a signal from the second satellite while generating the first beam. An antenna for use in satellite communications, characterized in that: According to clause 17,
The one or more processors generate first and second sets of first and second sets of radio frequency (RF) radiating antenna elements, respectively, of the antenna aperture to generate respective first and second beams to point to carriers at different frequencies. An antenna for use in satellite communications operable to generate first and second patterns for application to a second set, wherein the first and second sets of RF radiating antenna elements differ. According to clause 18,
An antenna for use in satellite communications, wherein the first and second sets of RF radiating antenna elements have different numbers of RF radiating antenna elements. According to clause 18,
The first and second sets of RF radiating antenna elements are in a ring around a central feed for the wave, furthermore each ring of the first set of RF radiating antenna elements is positioned at a ring of the RF radiating antenna elements of the second set of RF radiating antenna elements. An antenna for use in satellite communications, characterized in that it is located between rings. According to clause 18,
The first and second sets of RF radiating antenna elements are in a ring around a central feed for the wave, the first set of RF radiating antenna elements being closest to the central feed compared to the ring of second set of RF radiating antenna elements. An antenna for use in satellite communications, characterized in that it is located in a ring. According to clause 15,
An antenna for use in satellite communications, wherein the second beam points to the predicted location of the second satellite. According to clause 22,
An antenna for use in satellite communications, wherein the predicted position is based on a commanded two-line element (TLE). According to clause 15,
Satellite communication, wherein the first and second beams have different antenna gains, and when the second beam is used to acquire a signal from the second satellite, the gain for the second beam is lower than the gain for the first beam. Antenna for use in. According to clause 15,
An antenna for use in satellite communications, wherein the second beam is wider than the first beam when used to acquire signals from the second satellite.

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